Regarding quantum cryptographic communication, a research project called SECOQC (which stands for Secure Communication based on Quantum Cryptography) is known. In SECOQC, a function is proposed for performing key exchange on the basis of random numbers that are generated by means of quantum key distribution (QKD) and that are dispersedly stored in a plurality of nodes, as well as a technology is proposed for a protocol named Q3P (which stands for Quantum Point to Point).
The QKD technique is one of the techniques for achieving sophistication in the next-generation communication security, and the security of the QKD service itself is an important factor. Thus, for example, QKD is a breakthrough technology that can provide an absolutely secure communication environment.
However, the new type of communication technology such as QKD has a different technological principle than the communication networks or the communication services that already exist and are in use. Hence, it becomes necessary to design a new system compatible to the new communication technology, and it is not easy to apply that new system to the existing communication networks or the existing communication systems. In this way, if a new system that is designed for secure communication is to be applied to an existing communication network, then the differences in the technological principles and the configurations requires making alterations in existing terminals.